U.S. patent application number 12/745785 was filed with the patent office on 2011-03-03 for gas burner with improved primary air duct.
This patent application is currently assigned to ELECTROLUX HOME PRODUCTS CORPORATION N.V.. Invention is credited to Piero Armanni, Nico Biagioli, Marco Starnini.
Application Number | 20110048400 12/745785 |
Document ID | / |
Family ID | 39521808 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110048400 |
Kind Code |
A1 |
Biagioli; Nico ; et
al. |
March 3, 2011 |
GAS BURNER WITH IMPROVED PRIMARY AIR DUCT
Abstract
Gas burner, particularly for household cooking appliances, with
an horizontal or vertical gas supply conduit (1), a burner body
with one more flame crowns, an horizontal or vertical Venturi (4),
a nozzle (5) to inject the gas flow from said gas conduit into said
Venturi pipe and, means to provide the primary air flow which
include a tubular conduit which is coaxial and placed outside said
gas conduit, and an opening to allow the gas flow, placed between
said nozzle and the inlet of the Venturi pipe. The coaxial conduit
draws the respective air flow from a zone inside the body of said
cooking appliance, and said opening allows the passage of the
respective primary air flow sucked and coming from over the
appliance top surface (12). In order to stir the primary air flow
passing through said coaxial conduit, a plurality of radial wings
(10A) is arranged, said wings being shaped either planar or
helical, and being connected on the outer surface of said gas
supply conduit.
Inventors: |
Biagioli; Nico;
(Sansepolcro, IT) ; Armanni; Piero; (Forli,
IT) ; Starnini; Marco; (Forli, IT) |
Assignee: |
ELECTROLUX HOME PRODUCTS
CORPORATION N.V.
Zaventem
BE
|
Family ID: |
39521808 |
Appl. No.: |
12/745785 |
Filed: |
December 4, 2008 |
PCT Filed: |
December 4, 2008 |
PCT NO: |
PCT/EP08/66833 |
371 Date: |
October 27, 2010 |
Current U.S.
Class: |
126/39E |
Current CPC
Class: |
F23D 2900/14701
20130101; F23D 2900/14062 20130101; F23D 14/06 20130101; F23D 14/64
20130101 |
Class at
Publication: |
126/39.E |
International
Class: |
F24C 3/08 20060101
F24C003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2007 |
EP |
07123470.2 |
Claims
1. Gas burner for cooking gas appliances, and particularly for
household cooking hobs, comprising: a burner body (2) on which one
or more flame crowns (3B, 3C) are mounted, a Venturi pipe (4), a
gas conveying conduit (1), extended on horizontal or on vertical,
and terminating with a nozzle (5) inside said burner body, apt of
injecting the gas flow from said conveying conduit (1) into said
Venturi pipe (4), means to provide the suction of the primary air
flow, including two different inflow paths: wherein a first path
comprises a conduit (6), which is arranged around said gas
conveying conduit (1) and coaxial to it, forming a prolonged
annular interspace (7), and wherein the second path comprises a
through opening (8) arranged in a position downstream said nozzle
(5) and upstream the inlet to said Venturi pipe (4), said coaxial
conduit (6) being apt of drawing the relevant primary air flow from
an inner zone of said cooking appliance, said opening (8) being
able of allowing the intake of the respective primary air flow
which is sucked and comes from the upper zone of said cooking
appliance, characterized in that: air turbulating means are
provided, able of stirring the primary air flow in said coaxial
conduit (6), and which are lodged inside said annular interspace
(7), extending from the outer surface of said gas conveying conduit
(1) to the inner surface of said coaxial conduit (6).
2. Gas burner according to claim 1, characterized in that said
stirring means comprise a plurality of wings (10), radially
arranged with respect to the axis (X) of said gas conduit (1),
3. Gas burner according to claim 1, characterized in that said
stirring means comprise a plurality of wings (10A), helicoidally
arranged with respect to the axis (X) of said gas conduit (1), and
on the outer surface (11) of it.
4. Gas burner according to claim 1, characterized in that said
coaxial conduit (6) is placed in correspondence to the end portion
and around the outer surface (11) of said gas conduit (1).
5. Gas burner according to claim 1, characterized in that said
coaxial conduit (6) and said Venturi pipe are horizontally
oriented, and that said coaxial conduit is provided with a
prolongation (9) extending ahead and towards said Venturi pipe (4)
until substantially joining its inlet mouth, and in that said
through opening (8) is arranged in said prolongation (9), said
opening (8) being is placed in the upper portion of said
prolongation (9).
6. Gas burner according to claim 1, characterized in that said gas
conduit (1), said Venturi pipe (4) and said coaxial conduit (6) are
vertically oriented and are basically aligned, and that said
through opening (8) is made by a cylindrical or frustum-conical
opening at 360.degree. having its axis aligned or parallel to the
axis of said Venturi pipe (4), and is delimited on one side by the
inlet mouth of said Venturi pipe (4) and on the opposite side by
said coaxial conduit.
7. Cooking appliance, particularly cooking hob, comprising a burner
according to one of the previous claims, characterized in that it
is provided with an upper plane or surface (12) which partially
forms the lower side of the suction inflow channel (13) of said
second path and which enters said through opening (8).
8. Cooking appliance according to claim 7, characterized in that
the inlet mouth (14) of said inflow channel (13) is arranged
exactly over said upper surface (12).
9. Cooking appliance according to claim 8, characterized in that in
correspondence to said inlet mouth (14), said upper plane (12) is
being formed with a relief shape (15).
10. Cooking appliance according to claim 9, characterized in that
said relief shape (14) is made up by working said upper plane (12).
Description
[0001] The present invention relates to a gas burner, preferably of
the type generally used in the household cooking gas appliances and
in particular gas built-in hobs, provided with improved means to
convey the primary air into the Venturi pipe.
[0002] In the following of this description it will be referred to
a gas burner provided with both a central body with a peripheral
flame crown, and a perimetral body provided with two flame crowns,
oriented inwards and outwards, but it will be intended that what
explained may be identically applied and therefore valid also for
gas burners provided with only a peripheral body, that is without
the central flame body.
[0003] It is known that in such kind of cooking gas appliance two
main requirements are present:
[0004] a constructional and assembly requirement, i.e. the cooking
gas appliance, particularly when it is a gas hob, has to show a
minimum height, due to constraints which are well known to the man
skilled in the art, and therefore will not be repeated, and
[0005] a functional requirement, consisting in that the burner,
specially those burners with limited diameter, are requested to
provide in any case a suitable thermal power, and in any case the
maximum possible power.
[0006] These two requirements are however in apparent contradiction
to each other, as the need to keep down the total gas appliance
height obliges to also keep down the same height of the Venturi
pipes providing the gas to the burners; however such limitation
operates also as a limitation for the amount of gas/air mixture
which can be produced, and therefore determines the limit of the
burner thermal power.
[0007] In order to overcome such reciprocal conditioning, some
cooking appliances have been proposed and divulged, which are
provided with one ore more Venturi pipes which are horizontally
extended as for instance in the patents WO 2005/078342 and WO
2007/012766.
[0008] It is apparent that by horizontally placing the Venturi
pipes, it is automatically void the problem of their height which
conditions the overall height of the cooking appliance.
[0009] Moreover the two cited patents show respective solutions
wherein the Venturi pipes leave from the burner central zone and
branch out radially; therefore their total length is limited by the
radius, that is by the horizontal size of the burner itself.
[0010] In order to eliminate such condition it was proposed, for
instance in EP Publication 1120603 and in EP Application n.
07119078.9 a type of burner wherein the Venturi pipe is placed into
horizontal for the whole width, that is basically for the diameter
of the burner body itself.
[0011] However the showed solutions suffer from a quite common
drawback in such type of burners, that is from the fact that the
primary air is sucked and sent to the inlet of the Venturi pipe
from one access way only, i.e. either from the inner box body of
the cooking appliance, or from the outer room, that is from the
zone over the cooking hob itself.
[0012] Of course such circumstance does limit the total amount of
the available primary air, and therefore limits the available
thermal power.
[0013] In order to increase the primary air inlet flow, it was
proposed to intake and convey the primary air flow through a
coaxial and preferably tubular conduit, the final portion of which
ending with the gas injection nozzle.
[0014] Such solution is for instance divulged in the patents:
[0015] a) US 2006/0199119, [0016] b) U.S. Pat. No. 6,951,454,
[0017] c) JP 3-244906, [0018] d) JP 3-244905, [0019] e) US
2005/0279862.
[0020] However no one of said patents suggest, and even less
divulgates, the solution which shows that the primary air flow,
bound to the Venturi pipe, is taken from two distinct access ways,
that is from a conduit which is coaxial to the gas conduit, and
also from an opening which is independent of said coaxial
conduit.
[0021] It would therefore be desirable, and is actually a main
purpose of the present invention, to implement a kind of burner
provided with two different and distinct inlet ways for the primary
air flows to the Venturi pipe made up by a conduit which is coaxial
to the gas conduit, and by an opening or gate placed just after the
gas injection nozzle, wherein said access ways are independently
flown with air taken from the inside of the box body of the cooking
appliance, and from the outer room over it.
[0022] However such purpose turns to be profitable not only with
gas conduits and related Venturi pipes when horizontally oriented,
where the benefits are more apparent, but also with cooking
appliances provided with gas conduits and Venturi pipes which are
vertically oriented, even if some drawbacks may be experienced
caused by the height of the cooking appliance, yet the same the
same benefits due to a double primary air suction are achieved,
i.e. from the inside of the cooking appliance body, and from the
outer room over it.
[0023] According to the present invention, this and further aims
are reached in a kind of burner provided with a Venturi pipe which
can be either horizontally or vertically extended, which is
provided with connecting and inlet conduits for the primary air
flow incorporating the characteristics as recited in the appended
claims and including such operating means as described below by
mere way of non-limiting example with reference to the accompanying
drawings, in which:
[0024] FIG. 1 is a perspective outer view of a burner body and of
the relevant cooking gas appliance, here represented by a gas hob,
according to a first embodiment of the invention,
[0025] FIG. 2 is an exploded view of the cooking burner shown in
FIG. 1,
[0026] FIG. 3 shows a vertical and side section view according to
the section A-A of the assembly of FIG. 1,
[0027] FIG. 3A shows a section view, which is orthogonal to the "X"
axis of the gas conduit, of a detail of the burner assembly of FIG.
3,
[0028] FIG. 4 shows a vertical and side section view according to
the section A-A of a different embodiment of the assembly of FIG.
1,
[0029] FIG. 4A shows a section view, which is orthogonal to the "X"
axis of the gas conduit, of a detail of the burner assembly of FIG.
4,
[0030] FIGS. 5 and 6 do show perspective views of the details
respectively shown in FIGS. 3A and 4A,
[0031] FIG. 7 shows a view which is equivalent to FIG. 3, but
referred to a cooking appliance provided with a gas conduit and a
Venturi pipe which are vertically oriented.
[0032] With reference to FIGS. 1 to 4, a cooking appliance
according to the invention comprises:
[0033] a gas supply conduit 1 horizontally oriented,
[0034] a burner body 2 on which one or more flame crowns 3B, 3C . .
. are mounted,
[0035] a Venturi pipe 4 which is also extended into horizontal, and
is substantially aligned with the final portion of said conduit
1,
[0036] an gas injection nozzle 5 at the end of said conduit 1
towards said Venturi pipe 4.
[0037] The primary air is being conveyed towards said nozzle 5 and
into said Venturi pipe through two different flowing paths,
i.e.:
[0038] the first path consists of a suction air flow beginning from
inside the body of the cooking appliance, and which in its end
portion takes the form of a conduit 6 coaxial with said first gas
conduit 1, having a preferably tubular shape, and which surrounds
it at least in the end portion; therefore between said gas conduit
1 and said coaxial conduit 6 a prolonged annular interspace 7 is
formed, in which flows a share of the primary air, sucked by the
Venturi pipe.
[0039] As clearly shown in the figures, said coaxial conduit 6
stretches towards said Venturi pipe 4, to which it joins through a
suitable prolongation 9; as a matter of facts, it may be observed
that the Venturi pipe is merely the properly shaped continuation of
said prolongation 9, which to its time stretches ahead beyond said
injector 5;
[0040] the second path consists of a channel 13 whose suction mouth
opens over of the upper plane 12, and in its end portion a through
opening 8 is arranged, preferably placed on a side of said
prolongation 9, just downstream of said injector 5 and upstream of
said Venturi pipe 4.
[0041] Said through opening 8 then allows the primary air flow to
pass from the outer room towards said Venturi pipe 4, so achieving
the first invention goal, i.e. to make the primary air to intake by
splitting the whole flow into two separate flows, one of which
being arranged over said upper plane 12, and the other being
conveyed from the inside of the cooking appliance and which in its
end path enters into a conduit which is coaxial to the gas
conduit.
[0042] The just described solution allows some profitable
improvements; the first improvement consists in that, as shown in
FIGS. 3 and 4, said coaxial conduit 6 draws the relevant primary
air flow directly from the inner volume delimited by the box body
34 of the cooking appliance, while instead said opening 8 is
connected to the outer room, and exactly from over its top
surface.
[0043] This circumstance favors a better air flowing in the case
that the cooking appliance is undesirably lodged in such a way that
the air circulation is obstructed or slowed down; moreover the two
primary air flows, so conveyed, do not interfere in any working
condition.
[0044] Also it is preferred that said opening 8 is placed upwards
in said prolongation 9, so as to shorten and to make straighter the
path of that share of primary air flow coming from over the cooking
appliance.
[0045] Such solution is suitable to match the temperature increase;
since the heating from the burner reduces the density of the
primary air, it is important to improve the primary air flow, in
order to avoid compromising the burner functionality (combustion
performances, yellow tipping and soot).
[0046] In order to improve the mixing of the gas with the primary
air, it was experienced as an useful improvement to arrange some
means able of causing a turbulence in gas flow when coming out from
the conduit 1, so that the gas flow itself is being broken and
therefore it is easier mixed with the primary air flow.
[0047] It was then found profitable to arrange some suitable means
able of creating a turbulence in the air passing through said
interspace 7, so that the air going out from it, and basically from
said coaxial conduit 6, is soon mixed both to the gas exiting from
the conduit 1, and to the primary air flow entering from said
opening 8.
[0048] Such complete and prompt mixing effect both with the gas and
with the primary air flow obviously causes the mixture itself to
become optimized, what improves the combustion performances.
[0049] To this purpose, inside said interspace 7 and on the outer
surface 11 of said gas conduit some stirring wings 10 are arranged;
according to the turbulence effect which is wanted, and also to the
diameter of the coaxial conduit 6 itself, the two following
embodiments are proposed:
[0050] in the first embodiment and with ref. to the FIGS. 4 and 4A,
said wings 10 are flat, are preferably passing on the "X" axis of
said gas conduit 1, are radially oriented on the outer surface of
the gas conduit 1, are regularly distributed at the same angular
distance to each other, and preferably are quite prolonged so as to
be extended for the whole length of said coaxial conduit 6.
[0051] in the second embodiment and with ref. to FIGS. 5 and 5A,
said wings 10A are bent and specifically are placed in an helical
arrangement, as a screw thread, whose inner edge is still attached
on the outer surface of the gas conduit 1; said wings 10A too are
regularly distributed with the same angular distance, and
preferably are quite prolonged so as to be extended for the whole
length of said coaxial conduit 6.
[0052] The two just described improved embodiments are obviously
helpful to make up a cooking appliance which is particularly
effective not only from the point of view of the thermal power
supply, but also which is compact and especially cheap and simple
in the construction; moreover the invention may be highly
appreciated also due to the advantage that the nozzle replacement
may be carried out without any need to open the appliance, as this
operation may be performed across said opening 8.
[0053] As just described, the shown embodiments may be implemented
by a gas conduit and a Venturi pipe which are horizontally
oriented, as represented in the FIGS. 2, 3 and 4; however, as
previously remembered, it is also possible to make up the invention
by placing the gas conduit and the relevant Venturi pipe vertically
oriented, as schematically shown in FIG. 7.
[0054] In said case it has been proved that the most suitable
embodiment, both from a functional and a constructive point of view
is offered by the FIG. 7 itself, wherein said Venturi pipe is
substantially separated from the coaxial conduit 6 (differently
from FIG. 3, wherein said devices are interconnected by said
prolongation 9).
[0055] Therefore the outlet mouth of the conduit 6 is completely
opened, and so the air path, coming from the outside and sucked
into the channel 13, crosses an opening 20 showing a substantially
cylindrical or frustum-conical shape, extended on the horizontal
plane for 360.degree., and connecting the outlet mouth 6A of the
coaxial conduit to the inlet mouth 4B of the Venturi pipe 4.
[0056] Furthermore, and preferably, said same upper plane 12 makes
also the lower side of the channel 13 through which the primary air
is sucked into said second path and is conveyed into said opening
8.
[0057] So the inlet 14 of said channel 13 is then opened just over
said upper plane 12; moreover, in correspondence of said mouth 14
said surface 12 takes a profile in relief 15, so as the incidental
liquids and cooking remnants are prevented from entering said
channel 13; advantageously said relief profile 15 may easily be
obtained by a proper pressing/bending operation of this same upper
plane 12.
* * * * *